A variety of devices exist that move automatically over surfaces of swimming pools to be cleaned. One such pool cleaner operates in cooperation with the reduced pressure caused by a pump to induce debris-laden fluid within a pool to flow through the cleaner (and other filtration equipment if desired). The cleaner functions by causing a valve, or diaphragm, to oscillate, periodically interrupting the fluid flow through the cleaner. This periodic interruption in turn causes movement of the device over the surface to be cleaned. Suitable valves or diaphragms for such a fluid-interruption cleaner are described in U.S. Pat. Nos. 4,642,833 and 4,742,593, which patents are incorporated herein in their entireties by this reference.
U.S. Pat. No. 5,014,382, also incorporated herein in its entirety by reference, discloses one such fluid-interruption version of an automatic swimming pool cleaner. As described in the patent, the cleaner preferably includes a tubular resilient diaphragm to interrupt the flow of fluid (such as water) through the cleaner during use. The diaphragm entrance is typically located adjacent the inlet foot of the cleaner, while its exit communicates with an inner tube circumscribed by the cleaners rigid extension pipe (outer tube). Because the cleaner's exterior body (together with the inlet foot and inner tube) fix the diaphragm in position, the diaphragm is not easily removed from the cleaner for repair or replacement. Moreover, the rigid structures can accommodate only a single size diaphragm. As a result, not only must diaphragm manufacturing tolerances be minimized, but substitution of diaphragms of different lengths is precluded as well.